perf stat: Fix and validate CPU map inputs in synthetic PERF_RECORD_STAT events

Stat events can come from disk and so need a degree of validation. They
contain a CPU which needs looking up via CPU map to access a counter.

Add the CPU to index translation, alongside validity checking.

Discussion thread:

  https://lore.kernel.org/linux-perf-users/CAP-5=fWQR=sCuiSMktvUtcbOLidEpUJLCybVF6=BRvORcDOq+g@mail.gmail.com/

Fixes: 7ac0089d ("perf evsel: Pass cpu not cpu map index to synthesize")
Reported-by: Michael Petlan <mpetlan@redhat.com>
Suggested-by: Michael Petlan <mpetlan@redhat.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dave Marchevsky <davemarchevsky@fb.com>
Cc: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Lv Ruyi <lv.ruyi@zte.com.cn>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: netdev@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Monnet <quentin@isovalent.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: Yonghong Song <yhs@fb.com>
Link: http://lore.kernel.org/lkml/20220519032005.1273691-2-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/stat.c

@@ -472,9 +472,10 @@ int perf_stat_process_counter(struct perf_stat_config *config,
 int perf_event__process_stat_event(struct perf_session *session,
 				   union perf_event *event)
 {
-	struct perf_counts_values count;
+	struct perf_counts_values count, *ptr;
 	struct perf_record_stat *st = &event->stat;
 	struct evsel *counter;
+	int cpu_map_idx;
 
 	count.val = st->val;
 	count.ena = st->ena;
@@ -485,8 +486,18 @@ int perf_event__process_stat_event(struct perf_session *session,
 		pr_err("Failed to resolve counter for stat event.\n");
 		return -EINVAL;
 	}
-
-	*perf_counts(counter->counts, st->cpu, st->thread) = count;
+	cpu_map_idx = perf_cpu_map__idx(evsel__cpus(counter), (struct perf_cpu){.cpu = st->cpu});
+	if (cpu_map_idx == -1) {
+		pr_err("Invalid CPU %d for event %s.\n", st->cpu, evsel__name(counter));
+		return -EINVAL;
+	}
+	ptr = perf_counts(counter->counts, cpu_map_idx, st->thread);
+	if (ptr == NULL) {
+		pr_err("Failed to find perf count for CPU %d thread %d on event %s.\n",
+			st->cpu, st->thread, evsel__name(counter));
+		return -EINVAL;
+	}
+	*ptr = count;
 	counter->supported = true;
 	return 0;
 }